102 



100-29 



It is probable that these rocks come from the metamorphic aureole 

 surrounding the great granitic intrusion which extends from the west coast to 

 the head-waters of the Aorere River, and from the Big River to the south 

 of the Karamea. No doubt actual occurrences jn situ will be recorded 

 when the geological survey of the area now in progress is completed. 



Fig- 



Fig. 3 



EXPLANATION OF PLATE IV. 



2. Mici'o. section of chiastolite slate from West Wanganui Inlet, West Nelson. 

 A large chiastolite crj^stal is showii. with characteristic carbonaceous inclu- 

 sions. The light part of the rest of the section is ciuartz, the darker portion is 

 biotite. Magnified 25 diameters, ordinary light. 



Micro, section of a trilling of cordierite, showing numerous inclusions. Magnified 

 25 diameters, crossed nicols. Specimen from Aorere River, West Nelson. 



Art. XIX. — Crater of Ngauruhoe. 

 By Dr. P. Marshall, M.A., D.Sc, F.G.S., University of Otago. 



[Read before the Otago Institute, \Oth November, 1908.] 



The earliest accounts of the crater of Ngauruhoe, by Bidwill and Dyson, 

 show that considerable changes have taken place since these pioneers made 

 the ascent of the cone. The former, in 1839, describes it as " the most 

 awful abyss that I ever looked into or imagined." The stones thrown in 

 did not strike the bottom in less than seven or eight seconds. It was im- 

 possible to get into the inside of the crater, as the sides seen were, if not 

 quite precipitous, actually. overhanging. Bidwill states that Ngauruhoe was 

 in a state of activity at the time of his visit, and the steam prevented him 

 from seeing more than 8 or 10 yards into the crater. 



This description applies perfectly to the crater at the present day if 

 the volcano be more than usually active and the crater is reached on the 

 south or east side. From other statements made by Bidwill it appears 

 probable that he ascended the mountain on the north or west, and on those 

 sides at the present time the crater-floor is almost level with the wall. It 

 is reasonable, therefore, to suppose that the crater is now very different 

 in form from what it was when Bidwill saw it. 



